[strong] Implement static restrictions on switch statement

test/mjsunit/strong/switch.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --strong-mode
+
+"use strict";
+
+function CheckSwitch() {

[rossberg, 2015/04/16 12:01:16]

I like this much better now.

+  let jumpStatements = [
+    "break; ",
+    "continue; ",

[rossberg, 2015/04/16 12:01:16]

Add break and continue to label.

[conradw, 2015/04/16 12:34:20]

Done.

+    "return; ",
+    "throw new TypeError(); ",
+    "if(1) break; else continue; ",
+    "if(1) {1+1; {break;}} else continue; "
+  ]
+
+  let otherStatements = [
+    "null; ",
+    "1+1; ",
+    "for(;false;) {break;} ",
+    "for(;false;) {1+1; {throw new TypeError();}} ",
+    "(function(){return});",
+    "(function(){throw new TypeError();});",
+    "{break; 1+1;} ",
+    "if(1) break; ",
+    "if(1) break; else 1+1; ",

[rossberg, 2015/04/16 12:01:16]

Also add the symmetric "if (1) 1+1 else break"

[conradw, 2015/04/16 12:34:20]

Done.

+  ]
+
+  let successContexts = [
+    ["switch(1) {case 1: ", "case 2: }"],
+    ["switch(1) {case 1: case 2: ", "default: }"],
+    ["switch(1) {case 1: case 2: ", "default: {}}"],
+    ["switch(1) {case 1: case 2: ", "default: 1+1}"],
+    ["switch(1) {case 1: break; case 2: ", "default: }"],
+    ["switch(1) {case 1: case 2: break; case 3: ", "case 4: default: }"],
+    ["switch(1) {case 1: if(1) break; else {", "} default: break;}"]
+  ]
+
+  let strongThrowContexts = [
+    ["switch(1) {case 1: 1+1; case 2: ", "}"],
+    ["switch(1) {case 1: foo: break foo; case 2: ", "}"],
+    ["switch(1) {case 1: foo:", " case 2: }"],
+    ["switch(1) {case 1: foo:{ ", "} case 2: }"],
+    ["switch(1) {case 1: foo:{ ", "} default: break;}"],
+    ["switch(1) {case 1: { foo:{ { ", "} } } default: break;}"],
+    ["switch(1) {case 1: { { { ", "} 1+1;} } default: break;}"],
+    ["switch(1) {case 1: if(1) {", "} default: break;}"],
+    ["switch(1) {case 1: foo:if(1) break; else {", "} default: break;}"]
+  ]
+
+  let sloppy_wrap = ["function f() { for(;;) {", "}}"];
+  let strong_wrap = ["function f() { 'use strong'; for(;;) {", "}}"];
+
+  for (let context of successContexts) {
+    let sloppy_prefix = sloppy_wrap[0] + context[0];
+    let sloppy_suffix = context[1] + sloppy_wrap[1];
+    let strong_prefix = strong_wrap[0] + context[0];
+    let strong_suffix = context[1] + strong_wrap[1];
+
+    for (let code of jumpStatements) {
+      assertDoesNotThrow(strong_wrap[0] + "switch(1) {case 1: " + code + "}}}");

[rossberg, 2015/04/16 12:01:16]

Why not move this case to the successContexts?

[conradw, 2015/04/16 12:34:21]

The successContexts are intended to not work if code is not a jump (so I can
have throwing tests inserting otherStatements). If this case was added, line 76
wouldn't come out so neat, since there's no fallthrough from the last case.

+      assertDoesNotThrow(strong_prefix + code + strong_suffix);
+      assertDoesNotThrow(strong_prefix + "{ 1+1; " + code + "}" +
+                         strong_suffix);
+      assertDoesNotThrow(strong_prefix + "{ 1+1; { 1+1; " + code + "}}" +
+                         strong_suffix);
+      assertDoesNotThrow(strong_prefix + "if(1) " + code + "else break;" +
+                         strong_suffix);
+      assertDoesNotThrow(strong_prefix + "if(1) " + code +
+                         "else if (1) break; else " + code + strong_suffix);
+    }
+    for (let code of otherStatements) {
+        assertDoesNotThrow(sloppy_prefix + code + sloppy_suffix);
+        assertThrows(strong_prefix + code + strong_suffix, SyntaxError);
+    }
+  }
+
+  for (let context of strongThrowContexts) {
+    let sloppy_prefix = sloppy_wrap[0] + context[0];
+    let sloppy_suffix = context[1] + sloppy_wrap[1];
+    let strong_prefix = strong_wrap[0] + context[0];
+    let strong_suffix = context[1] + strong_wrap[1];
+
+    for (let code of jumpStatements.concat(otherStatements)) {
+      assertDoesNotThrow(sloppy_prefix + code + sloppy_suffix);
+      assertThrows(strong_prefix + code + strong_suffix, SyntaxError);
+    }
+  }
+
+  for (let code of otherStatements) {
+    assertDoesNotThrow("switch(1) {default: " + code + "}");

[rossberg, 2015/04/16 12:01:16]

Same here?

[conradw, 2015/04/16 12:34:21]

Similar reasoning. This for block is a specific (over)reaction to my mistake
with the right bracket condition.

+    assertDoesNotThrow("switch(1) {case 1: " + code + "}");
+    assertDoesNotThrow("switch(1) {case 1: break; default: " + code + "}");
+    assertDoesNotThrow("switch(1) {case 1: " + code + "break; default: }");
+  }
+}
+
+CheckSwitch();
+
+assertDoesNotThrow("'use strong'; switch(1) {}");

[rossberg, 2015/04/16 12:01:16]

Can't you cover all these by adding "" to the otherStatements?

[conradw, 2015/04/16 12:34:21]

It's currently assumed that when one of the otherStatements is used as "code"
with a successContext, it will throw in strong mode. Including "" would create
empty statements in many cases, causing "allowed fallthroughs", and no throws.
The original intention of this section was to test switches with various
"especially empty" bodies that didn't fit neatly into one of the lists, but I've
ended up with some duplicated tests. Will fix.

+assertDoesNotThrow("'use strong'; switch(1) {case 1:}");
+assertDoesNotThrow("'use strong'; switch(1) {case 1: case 2: default: }");
+assertDoesNotThrow("'use strong'; switch (1) { default: null; }");
+assertDoesNotThrow("'use strong'; switch (1) { case 0: case 1: null; }");
+assertDoesNotThrow("'use strong'; switch (1) { default: {} }");
+assertDoesNotThrow("'use strong'; foo: switch(1) {case 1: break foo;}");